tests/frontend/test_registration: Use pytest fixtures
tests/frontend/test_registration: Use pytest fixtures

... instead of TestController

RBE-Avionik/skylines,RBE-Avionik/skylines,Turbo87/skylines,RBE-Avionik/skylines,TobiasLohner/SkyLines,snip/skylines,skylines-project/skylines,kerel-fs/skylines,kerel-fs/skylines,shadowoneau/skylines,snip/skylines,TobiasLohner/SkyLines,snip/skylines,shadowoneau/skylines,Harry-R/skylines,skylines-project/skylines,Harry-R/skylines,shadowoneau/skylines,Harry-R/skylines,shadowoneau/skylines,skylines-project/skylines,kerel-fs/skylines,TobiasLohner/SkyLines,Turbo87/skylines,Harry-R/skylines,Turbo87/skylines,RBE-Avionik/skylines,Turbo87/skylines,skylines-project/skylines